Dmitry Vyukov <dvyukov@xxxxxxxxxx> writes: > From: Arnd Bergmann <arnd@xxxxxxxx> > Date: Sat, May 11, 2019 at 2:51 AM > To: Dmitry Vyukov > Cc: Nick Kossifidis, Christoph Hellwig, Linus Torvalds, Andrew Morton, > linux-arch, Linux Kernel Mailing List, linuxppc-dev > >> On Fri, May 10, 2019 at 6:53 AM Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: >> > > >> > > I think it's good to have a sanity check in-place for consistency. >> > >> > >> > Hi, >> > >> > This broke our cross-builds from x86. I am using: >> > >> > $ powerpc64le-linux-gnu-gcc --version >> > powerpc64le-linux-gnu-gcc (Debian 7.2.0-7) 7.2.0 >> > >> > and it says that it's little-endian somehow: >> > >> > $ powerpc64le-linux-gnu-gcc -dM -E - < /dev/null | grep BYTE_ORDER >> > #define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> > >> > Is it broke compiler? Or I always hold it wrong? Is there some >> > additional flag I need to add? >> >> It looks like a bug in the kernel Makefiles to me. powerpc32 is always >> big-endian, >> powerpc64 used to be big-endian but is now usually little-endian. There are >> often three separate toolchains that default to the respective user >> space targets >> (ppc32be, ppc64be, ppc64le), but generally you should be able to build >> any of the >> three kernel configurations with any of those compilers, and have the Makefile >> pass the correct -m32/-m64/-mbig-endian/-mlittle-endian command line options >> depending on the kernel configuration. It seems that this is not happening >> here. I have not checked why, but if this is the problem, it should be >> easy enough >> to figure out. > > > Thanks! This clears a lot. > This may be a bug in our magic as we try to build kernel files outside > of make with own flags (required to extract parts of kernel > interfaces). > So don't spend time looking for the Makefile bugs yet. OK :) We did have some bugs in the past (~1-2 y/ago) but AFAIK they are all fixed now. These days I build most of my kernels with a bi-endian 64-bit toolchain, and switching endian without running `make clean` also works. cheers
